A planetary gear comprises a planet carrier, a sun shaft, a gear ring, and planet wheels supported by the planet carrier so that the planet wheels are meshing with the sun shaft and with the gear ring. In cases where the gear ring is stationary, the gear ratio between the sun shaft and the planet wheel carrier is ZR/ZS+1, where ZR is the number of teeth of the gear ring and ZS is the number of teeth of the sun shaft. The planet carrier in its simple form comprises a first end-section for supporting first ends of the planet wheel pins and a second end-section for supporting the second ends of the planet wheel pins. The planet wheel pins can be attached for example with thermal shrink fits to the respective holes of the end-sections of the planet carrier. In order to increase the mechanical stiffness, the planet carrier may further comprise support sections between its end-sections.
Maintenance of a planetary gear comprises often, or at least sometimes, removal of one or more planet wheel pins from the planetary gear in order to be able to remove one or more planet wheels that need to be replaced with new ones or repaired. In many cases, maintenance work of the kind described above requires moving the planetary gear away from its operating site to a mechanical repair plant where there are appropriate means for detaching planet wheel pins from the planet carrier of the planetary gear and means for installing planet wheel pins on the planet carrier. Moving the planetary gear from its operating site to the mechanical repair plant can be a laborious task especially in conjunction with wind power applications where the operating site of the planetary gear is typically a nacelle that is located at the top of a tower.